Archives of the TeradataForum
Message Posted: Fri, 27 Feb 2004 @ 16:30:12 GMT
| Subj: || || Re: Derived tables on V2R5 |
| From: || || Fred W Pluebell |
I'd say the question is what you are trying to accomplish. If you want to use derived table expressions to combine what would otherwise be
multiple statements into a single query, that use is clearly still valid.
Derived tables have also been used as a "hint" to the optimizer regarding order of operations. I wouldn't call this use "obsolete" yet, since
you can still force the earlier behavior through the "SpoolDerivedTables" switch in dbscontrol. But I'd say such use is "discouraged", since the
default behavior in V2R5 is to attempt global optimization across views and derived table expressions. I could understand a vendor's reluctance to
develop a way to take advantage of a "feature" that Teradata is trying to phase out...